This application requests funding for a Clinical Trials Unit which will target pediatric, adolescent, and maternal HIV infection. The NJMS CTU is a longstanding center for clinical trials located in Newark (Essex County), New Jersey, an epicenter of HIV infection in the U.S. The CTU is an integral site within the Pediatric AIDS Clinical Trials Group (since its inception in 1991) and was one of the first two pediatric sites within the AIDS Clinical Trials Group. The CTU has been selected as a 'highly preferred Core'site by the new IMPAACT Network. With its stable core of experienced staff and large group of investigators, it is well positioned to make substantial contributions to the IMPAACT Network in the form of senior leadership and clinical trials participation. The NJMS CTU is composed of an Administrative Core, headed by the Principal Investigator and Research Coordinator, and a single Clinical Research Site (CRS). The CRS is composed of 3 clinical enterprises: Pediatric, Perinatal/Women's Health, and Adolescent, each of which is led by a Medical Director. In addition, there is a Clinical Trials Support Group (Research Nurses, Regulatory, Pharmacy, Laboratory, and Data Management), a Community Advisory Board, and a Fiscal Manager. The NJMS CTU, as a formally linked site with the new IMPAACT Network, proposes to address four high priority scientific areas: - Mother to Child Transmission (MTCT) - Optimization of Clinical Management, including co-morbidities - Translational Research/Drug Development - Vaccines for Prevention of Sexual Transmission ADMINISTRATIVE COMPONENT: